SDC1 and Miyoshi myopathy: While not unexpected, it was interesting to observe that the relative 13C labeling of the intermediates from the first turn of the TCA cycle in RPMI-8226 and MM1S HMCLs when cultured in media containing 5% enrichment with [13C5]-glutamine for 60 min (Supplementary Figure 2) was higher than observed in the CD138+ malignant plasma cells from MM patients who had similar levels of [13C5]-glutamine enrichment in their bone marrow plasma for approximately the same duration (Fig. 2b).